Telephone system



March 15, 1932. I H. HOVLAND 1,849,088

- TELEPHONE SYSTEM Filed May '14, 1950 s Sheets-Sheet 1 V OT- VEHT uvvmvrae H -HOVLAND B WM V ' a A TTUENC r March 15, 1.932. H. HOVLAND TELEPHONE SYSTEM 3 Sh ets-rsheejt 2 Filed May 14, 1930 /Nl/ENTOR H. HUI/LAND TTURNEY March 15, 1932.

H. HOVLAND TELEPHONE SYSTEM Filed May 14, 1930 3 Sheets-Sheet Patented Mar. 15, 1932" I m gs mm PATENT amer HENRY novLANn; OF'WILLISTON PARK, NEW;YOB.K, essrenoa o BELL rnnnrnoun LABORATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK Application filed m 14,

This'invention relates to telephone systems,

and in particular to party line telephone sysv vAn object of the invention, is to =simplify '5 and improve the signaling of party lines'ub scribers.

l-leretofore subscribers onja partyline have been signaled by having a connector switch select the party line through difierent-corre- '1 0 spending terminal points and this cause into a plurality of '20 respondingly responsive signaling appara-f t-us at the subscribers stations on the line.

In my copending' applicatiom-Serial. No. 452,155, iiled on the same date as this application is'disclo'sed a system of this kind in which signal current interrupters areindividualto the connectors and common control means are provided whereby whena connector seizes the party. linethrough any ofjthe ter minal to transmit the code signals.

7 A featureof this invention is a system of the same type as disclosed in the above mentioned copending application, in which an interrupter in the form of a marginal relay is provided for each connector with means points the individual interrupter is controlled 7 ivhereby said relay is controlled to transmit different kinds of signaling currents forthe code signals depending on the terminal point through which the connection is established,

Another feature is a system"whereby the connections to this marginal relay from the common control means are not completed until the common control ineansuis in condi;- tion to control the relay to transmit complete code signals, regardless of what time'the' con- 'nector com' plete's the connection j to the d.e-' sired l ne and in case said common means is inn e by another connector. p 7

T is inveut-ion'hasbeen 'llustrat'ed 1n the accompanying drawings in which:

' trolled'respectively by lays may be ofthe TELEPHONE: sYsTEM 1930. Serial No. 452,156.

' F 1 shows in general the'circuit connections for an eight party" subscriberls line; 1

Fig. 1A shows one party line'subscribers telephone circuit in detail.

- Fig.2 shows a connector clrcuitembodying the features of this invention; with a'selector switch in diagrammatic form for connectlng a calling subscriber through the connectorto a "called subscribefslin'e; f= d Fig. 3 shows a. circuitcommon to a plurality of connector circuits-tor supplying the tour different codes required in this system; and c Fig. 4 shows a'connector similar to that shown in Fig; 2fexcept' that it may be used for'extendingcalls from toll boards to. called subscriberslines.- r 7 Referring to Fig. 1,"an eight party linelO has been shown wlth the alternating current responsive relays of four subscribers con- ,nected to one conductor'and the alternating current responsive relays iofthe'other tour subscribers connected to: the 'other conduce tor. .The ringers for these eight subscribers have also been shown with their circuits conthese relays to connect the ringers to the line'conductors; The regeneral alternating current responsive type shown in the patent to Dean, 722,680 o f March 17,1903, while the ringers maybe of any' well known alternatingcurrent responsive type biased to respond to positive orneg'ative ringing currents. The ringers have-beenmarke'd with a plus or minus sign to indicate their operating characteristics and with a numeral 1 or 2 to; indicate the code I signal to which-the associated subscribers will respond. "In FigQlA is shownan'ordinary jsubscribers telephone circuit of the type] suitable toruse in party lines of the this'lrind with an alternating current responsivefrelay for closing the circuit for the associated ringer. :Eight sets of multipleter-minals forj thisline have been shown aty11 with a conhector 1.2 is diagrammatic form having access to these eight sets ofterminals. A s'elec-. V tor 14 has been shown in dagrammatic form and this selector may connector which in-turn may be actuated to select one of the'eight parties'througha corj responding set ofterminalsl The code signal to be transmitted to the desired party will then be selected and applied through the 'common equipment shown at 16 in diagrammatic form. The code signals will consist of one or two impulses of positive or negative ringing current transmitted over the tip or the ring conductor to control the relays to connect the ringers, and to control the ringers to respond to the proper code signal. The arrangement is such that if, for example, positive ringing current is applied to the left hand conductor in Fig. 1 the tour relays connected to this conductor will respond to the alternating current component of the ringing signal to close the ringer circuit at the associated subscribers stations. The two ringers marked with a plus sign will then respond to this positive ringing current signal while the ringers marked with a minus sign will remain unresponsive. Depending then on whether the code signal consists of one or two impulses a one ring code'signal will be answered only by the subscriber to which this code signal has been assigned whereas the subscriber assigned to respond to a two ring code signal will ignore the one ring code signal and vice versa.

Detailed descriptions will now be made of the functions of this system, in connection with a call from a subscriber on line through the selector 2]. and connector 22 to a subscriber on party line 23. A description will also be made of a call over the circuits shown in Fig. 4 from a toll board connected through conductors 300 and over selector 301 and connector 302 to line 303 of a desired subscriber, with .this line considered as a party line.

Referring now to the first type of connection, Figs. 2 and 3 may be considered connected together with 2 above Fig. 3. When subscriber on line 20 has selected through selector, 21 connector 22 a circuit is completed for the operation of the connector 22 toselect the desired subscribers line. This circuit will be completed from the loop of the calling subscribers dial through the tip and ring conductors over the make-before-break contacts of relay 25, winding of relay 26 to battery and ground.respectively. Relay 26 is thereby operated and an obvious circuit completed for the operation o1 relay 27. Relay 27 in operating connects at its inner lower armature and front contact a ground for the purpose of holding the pre cedingswitches used in this connection actuated. This relay also opens the circuit for the release magnet at its lower outer armature and back contact and prepares an operating circuit for the vertical magnetSO and a number of other circuits which will be described hereinafter. Relay 27 being slow to release remains operated during tie sending of the impulses for controllingthe connector. The first release of relay 26 in response to the inn pulses from the calling subscribers station, closes a circuit for the vertical magnet 30 from battery, winding of this magnet, winding or" the change-over relay 31, lower contacts of vertical oil-normal contacts 32, lower outer armature and front contact of relay 27, armature and back contact of relay 26 to ground. Both the vertical magnet and the change-over relay operate and change over relay 31 which is slow in releasing will remain operated during the succeeding in1 pulses transmit ed to the vertical magnet 30. W hen the vertical magnet has taken one step the original pulsing circuit is changed to pass through the lower make contacts of the vertical off-normal contacts 32 and thearmature and front contact of relay 31. The succeed ing impulses now cause the vertical magnet to advance the brushes 85 of the connector to the proper level in which the desired subscribers line is located.

hen the pulses cease relay 31 releases and prepares a circuit for the rotary magnet 36 from battery winding of magnet 36, fourth lower armatureand back Contact of relay 37, lower outer armature and back contact of relay 38, armature and back contact of relay 31, lower made contacts of the vertical olfnormal contacts 32, lower outer armature and back contact of relay 27 to ground at the armature and back contact of relay 26 when this relay releases in response to the first impulse. Relay 39 also operates on the release of relay 26 over a circuit from battery and the winding of this relay in parllel with the rotary magnet 36 over the same circuit traced for this magnet. When the relay39 operates the circuit for this relay will extend over its upper inner armature and front contact independent of the connection through the lower outer armature and back contact of relay 38. Relay 39 is also slow in releasing so that it will remain operated during the sending of the second series of impulses.

' Relay 39 now closes a circuit for testing the called line. If the line called is busy, ground will be found on the sleeve terminal of this line to cause the operation of relay 38 before relay 39 releases after the last digit has been transmitted. This circuit may be traced from battery; 'inding of relay 38, lower outer armature and back contact of relay 37,1ipper outer armature and front contact of relay 39 to ground at the sleeve conductor of the busy line and when relay 39 releases relay 33 will be locked through the make-beforebreak oi the relay 39 and the inner lower ,arn ature and front contact of relay 38 to ground the lower inner armature and front contact of relay 271' Relay 38 in operating applies a busy tone from the source 43 through the upper armature and front contact of relay 33 the ring conductor back to the calling subscribers line.

nsaaoes Ifon the other hand the called; lineisidle, relay 39' will release without. causing the. operation of relay 38- and the connection conipleted for the application. of ringing current.

The release of relay 39 closes acircuit for the partial operation of relay 37 from battery through the winding of the usual cut-off relay of the called line over the sleeve conductor,

upper outer armature and back contact of relay 39, upper winding of relay 37 lower inner armature and back contact ofrelay 38 to ground at relay 27. This ground will serve as a guard potential onthesleeve terminal for the calledline until relay 37 has fully operated. The partial operation of relay 37 closes a circuit, frombattery,the lower winding and lower inner armature and front contact'of relay 3? to ground at the upper inner armature and front contact of relay -27 to cause relay 37 to fully operate and close connections through the" remaining contacts. Relay 37, thereby, establishesconnections for ringing the called. subscriber as will hereina after be described.

When an idle connector has been found and actuated to select the set of terminal-"of the desired party line subscriber the common equipment shown in: Fig. 3- is actuated to transmit the proper code signal.- It should be observed that on the operationof relay 27 a circuit was completed for the starting of this common control equipment in Fig. 3 t

function to supply the ringing signal; I This circuit may be traced from battery winding of'start relay 200, lead 42, upper outer armature and front contactv of relay 27, middle lower armature and back contact of'relay 43,

outer right-hand armature and back contact of'relay 25 to ground. In Fig. 3 the switch 201 is provided with terminal banks 202' to 205. the. associated brushes of which are driven in a step-by-step manner by the stepping magnet 206 for the purpose of controlling the code signaling as well as the type of ringing current to be applied. When relay 37 operates, connector 22in conjunction with the common control equipment will be actuated to select the proper signaling code, In-

case the fourth'terminal of terminals 23- is associated through lead 44 with the right hand armature of relay; 207 this relay will control'the signaling. On the operation of rela-y'200 a circuit'is'completed from interrupter 208 for the operation of relay 209 umder control of the interrupter to actuate the stepping magnet 206 to step the switch 201 at the rate of one step for each operation of the magnet 205 which, as shown, is'controlled by relay 209 over an obvious circuit; Asnoted," the brush of bank202 will close circuits; for relay 207 as the brushv travels over the first V and third terminal, the eighth and tenth terminal, the fifteenth and seventeenthterminal for each revolution of the brush and thus cause relay 207 to be actuated twice at? short ,ductor 44, right-hand armature of relay 207 .tion of relay, 20.7 also causesa circuit to be closed forrelay 213 to operate this relay each thatswitch 201 is in normal position this circuit may 'be completed from battery wind- :ing of relay 48, lower outerarmature and back contact of relay 43, make-before-break contacts of relay "48, fourth lower armature and front-contact of relay 37, conductor 46,

brush of bank 205 in normal position to ground. Relay 48 inoperating provides *a locking circuit for itself independent of this ground over lead 46 to the upper armature and" front contact of relay 48 to'ground at relay 27 When theselector20l has taken one'stepthe ground on conductor46is moved so that if any other connector 'reaches the ringing stage at this time, its relay co-rre-' sponding to relay '48 will not operate and therefore prevent ringing until the nextcycle of the ringing interrupter is 1'eached,.tl1at is,

at the above mentioned posit-ions for bank 205. 1 Relay 207 is now oper'atedfroin the brush of bank 202 in positions 1 and 3, 8

and 10, Y15 and 17, to operate this relayt'o control the transmission-of a code of. two impulses of ringing current at fixed intervals; On each operation of relay 207 a circuit is completed for the operation'of relays 40and 41 as follows: from battery,-lower' winding of relay 4:1,windingof relay 40, p lower inner armature and front contact of v relay 48, the fourth terminal of line 23, con-- to ground. It will be notedthat the opera:

time relay 207 is operated. Relay 213 is slow to operate to permit the prioroperation'of relays; 40 and 41. The operationof relays 213, 40 and 41 now causes the transmission of a two-ringcode signal to the called line over a circuit as follows: from the positive ringing source 215, innerleft-hand armature and front contact of relay 2,13, inner lower armature and frontTcontact of relay 41, inner lower armature andyfront' contact of relay- 40, second upper arm'ature and front contact -of relay 41, upper winding of relay 43, up-

per inner armature and front contact of. relay 41, upper lnner armature and back contact of relay 43, inner upper armature and.

' front contact of relay 37 tethering conductor ,of'the party line 23 to the called subfscribers'relay- The called subsc'ribers alterhating current responsive-relay will now respond to this ringing signal't-o connect the associatedjringer across'the line so that this ringer may respondtothe positive two ring code signal. It should, of course, be observed" that the relays. of all four subscribers sets connected with this conductor will respond, but the positive two ring code signal will only cause the ringers responsive to a positive ringing signal to operate and a two ring code signal will be answered only by the subscriber to Whom this code signal has been assigned whereas the subscriber assigned-to respond to a one ring code signal will ignore the two ring code signal.

If theconnector 22 had selected terminals in which the tip and ring conductors had been reversed the relays of two of the sub scribers having them connected to the other conductor WOdll have responded the subscriber to which the two-ring positive code signal had been assigned would have answered the call. In case the subscriber assigned to a two-ring code and ha ng his relay r sponsive to negative ringing current, had

been desired, the connector would have selected another set of terminals in which the fourth terminal is connected to lead 217. In this case the circuits for'relays 4:0 and l1 would have 7 been completed to ground through a resistance 218. 31s relay ll is marginal it would not have operated'and ther fore curren from the negative source 220 would have been supplied through the outer left-hand armatureand front contact of relay 218, lower outer armature and front contact of relay 10, lower inner armature and back Contact of relay thinner lower armature and front contact of relay i0, iniddl upper armature and back contact ofrelay 11, upper winding of relay 13, upper outer armature and back contact of relay llover the ring conductor to the called subscribers relay. On the other hand, if the connector had selected a set of terr-inals in which the lead 222 had been connected to the fourth terminal a different code signal would have been transmitted. In this case relay 212 would have been operated in positions 1 to 2, 8 to 9 and to 16, so as to cause a single signaling impulse to be transmitted at these three sets of positions. In this case both relays 40 and n would have operated and a positive ringing signal of one impulse would have been re peatedly transmitted from source 215 to the called subscriber over the circuit heretofore traced when both relays are operated. And finally, if lead 224 had been connected to the fourth terminal of the set selected, relay 11 would not have operated due to the resistance 226 being inserted in the circuit completes to ground through the inner left-hand armature and front contact of relay 212 and. fore negative ringing current from sou c would have been transmitted the party line over the circuit hereinbefore when only relay 40 operates.

It is therefore evident that depending on how the fourth terminals are connected and. whether the tip and ring conductors have been reversed, the eightsubscribers bells on a party line may be actuated by distinctive ringing signals comprising one or two impulses from sources 215 or 220. As shown, the ringing current passes through the upper winding of relay 48 and when the called subscriber answers this relay operates to establish the connection, through tip and ring conductors. Relay 43 is first partially operated to close a circuit for the full operation of this relay through its lower winding from battery, lower inner armature and front contact to ground at the upper inner armature and front contact of relay 27. When relay 43 operates fully the ringing circuit is opened at the upper inner armature and back contact and the connection is cut through from the calling subscriber to the called subscriber over the upper armatures and front contacts of this relay. The operation of relay 43 also opens the holding circuit for relay 48 which is now released and opens the circuit over conductor 42 to release relay 200 which thereby causes switch 201 to be released from the control connector 22. 1

When relay 200 is released switch 201 will be returned to normal. Relay 230 is oper ated over an obvious circuit if the switch is in positions 1 to 5, 8 to 12 or 15 to 19, when relay 200 is released. Under these circumstances a circuit for the operation of the stepping magnet 206 will therefore be completed from battery winding of this magnet and its self-interrupting contacts, right-hand armature of relay 230, righthand armature and back contact of relay 200 to ground to cause switch 201 to be advanced to position 6, 1%, or depending on the position in which the switch is when relay 200 releases. When the switch arrives to either one of these positions the self-interrupting circuit for magnet 208 will again be completed through the brush of bank 203 to ground to advance the switch to the nearest normal position. It should be noted that in case this circuit has been closed to advance the switch. to position 7 or 14:, this self-interrupting circuit will not be opened in these positions and that in case the switch has been advanced to position 21 it will again be advanced to the Zero position. The switch will then remain in position 7 14:, or 0 until again talren for use. This switch has therefore. three normal positions and ma be started from either of these positions by the ground provided on the brush of bank 20 to lead 46. I

When the conversation is completed and if the called subscriber disconnects before the calling subscribers relay 25 will release and when the calling station disconnects relays 26 and. 27 are released causing relays 43, 37 and 42 to release- The releasing magnet 51 will then have its energizing circuit completed to returnthe switch to normal. lhis circuit maybe traced from battery winding contact of relay137, lower outer armature and back contact of relay 27 tofground at the armature and back contact of relay 26. When the switch has returned to normal, the vertical off-normal contacts 32 open the circuit for magnet 51.

If the calling subscriber disconnects before the called subscriber,-relays 26 and 27 will release whereasrelay 25 will remain operated to hold relays 43 and 37 thus maintaining the holding circuit for relay 25 until the called subscriber hangs up his-receiver. However, before the release of relay-27 amomentary circuit is completedfor relay .39 as follows: from battery, winding of this relay lower outer armature and: back contact ofnrelay 38, armature and front contact of. relay 31, vertical ofil-norma-l contacts 32, lower outer armature and-front contact of relay 27, armature and back contact of relay 26. Relay 39 in op; crating momentarily removes thef'ground from thesleeve of selector2l to cause the preceding switchesto release. When relay .271

releases, relay 39 releases. and, thereby again,

applies a ground to the sleeve to guardcon-H nector 22 against seizure-before its release.

When the called subscriber releases, the conforman'ce of the common control equipment.

For example, if fOI'zSOIIlB reason or another a false ground connectionis 'made on lead 46 while relay 207 is operated a .circuit'will:

be completed for the operation of relay 233. This relay will op'erateand lock itself to'this ground over its right-hand armature and.

front contact. A circuit is thereby closed for the operation of relay 234 and the lighting of lamp 235. Relay 234 closesan alarm-.cin. cuit connectedat 236, not shown, and the lighting of the lamp will indicate that the system had not functioned properly in this re-- 1 spect. If the switch 201 fails to operate when,

the starting relay 200 is operated a circuit will be completed for the operationofrelay 237, when interrupter238 closes a circuit to battery. This circuit may be traced from I battery, interrupter 228, right-hand winding of relay 237', make-before-break'contacts of" this relay, lamp 239, armature and back con-1 tact of relay 240 to ground at the right-hand armature and front contact, of relay; 200.. Then whenthe interrupter 241 applies ground to the fight-handarrnatureof relay 237a cir-' cuit is completed-for the operation of relay 242 which in turn closes a circuit for the op' eration of relay 234' to establish the alarm circuit. Relays 242 and 237 provide a lock-' 1 ing circuit for themselves to the circuit established by relay'200; :vIf the selector 201 fails to return to any ofits normal positionswhen relay 200 releases, relay 230 will remain operated and cause an alarm circuit to be closed by the operation of relays '237', 242

and. 234 andv the lamp 239 will be lighted to indicate this trouble. If there is aazfals'e groundflconnection on anyof the leads con-.

control circuitshown in Fig.3 in the same manner as the connector inl ig. 2 islassoe ciated with-thiscircuit. When selector 301 seizesconnector302,ground is placedon the 1 sleeve lead and through th'e' secondlower.

armature and-back contact of relay 105.; This;

gro'undis'thereb-y also placed .on the fourth. leadto-the selector301 for purposes. as will nector. circuit may be 7 associated LWibll: the

hereinafter be. explained. Belay 304 .is also' operated. on the "seizure of theconnector from battery; and ground through the two windings of thisrlelay, upper ar'matures and back contacts of relay 305, tip. and ring 'conduc tors, selector 301 trunk 30:0 throu glithe. opera 'tors at the toll board; lielayj 304 in operatingrnow "closes a circuit for relay 306 fromv battery, lowenwindin'g of this-relay, right=hand armature and frontcontact of relay 304, second lowerarm'ature and back contact of relay 1305 to ground-. Relay 306 in operating provides ailockin gfcircuit for itself from battery, thelower winding and lower armature and front contact of relay 306,1owerarmature and back contact of relay. I 307, second-lowerarmatureand back contact of relay 305,, to the sleeve terminaliof selector 301 to ground. .Relay306 opens a circuitfor. the release magnet 308 at the second lower armature and back contact and prepares apulsing circuit for the vertical magnet 309.

On the first release of pulsing-relay 304inresponse to the first series of impulses for-the control of this switchfa circuitwill be com pleted' for the-vertical magnet andthe changeover r'elayf310 as' follows: Battery, windings of magnet 309', and relay 310 in 'se'riea'ver tical pH-normal contacts 311, second lower armature and front contact of relay 306, right-hand armaturejand back contact. of

vrelay to ground at the secondflowerarmature andba'ck contact of 'rel'ay 3015 R ck lay 310 is slow in releasing so that it will re-v main operated during the sending of tlieimf pulses to the vertical magnet. When relay 310 operates the circuitforfthe sncceeding impulses to f the ,vertical ;1nagnet, ;will, pass through they armature and front contact of of selector 301.

erated partially to close its operating circuit.

relay 310 and made contacts of vertical olfuormal contacts 311.

. After the first series of impulses have been receivedto raise the brushes of switch 302 to the level in which the desired subscribers line is located, relay 310 releases and transfers the pulsing circuit to the rotary magnet 313. This circuit will also pass through the winding of relay 314 as follows: battery, windings of magnet 310 and relay 314 in series, armature and back contact of relay 31-0, vertical off-normal contacts of relay 311, second lower armature and front contact of relay 302, right-hand armature and back contact of relay 304 to ground at the second lower armature and back contact of relay 305. The second series of impulses will now cause the operation of relay 314 and the rotary magnet will advance the brushes of switch 302 to the desired subscribers party line terminals. Relay 314 is slow in releasing and will remain operated for a short period after the pulsing is completed to prepare a busy test circuit. If the selected line is busy there will f be a ground connection-on the sleeve terminal to cause the operation of relay 307 before.

relay3l4 releases. This circuit may be traced from battery, winding of relay 307, armature and front contacts of relay 314 to ground on the sleeve. Relay 307 prepares a locking circuit for itself which will be closedthrough the make-before-break contacts of relay 314 when it releases, upper'inner armature and front contact of relay 307, left-hand armature. and front contact of relay 304, upper Winding of relay 305, to ground on the sleeve Relay 305 is thereby opfrom battery through its lower winding and lower inner armature and front contact to ground on the sleeve of selector 301.. Relay 305 is thereby completely energized to operate all its armatures. The locking circuit for relay 307 will now receive its ground con-' nectionfrom the ground at the fourth lower armature and frontccontact of relay 305. The operation of relays 30'. and 305 also changes the holding circuit for relay 306 which now extends from battery, lower wind- 1 ing of relay 306, lower inner armature and front contact of this relay, lower armature and front contact of relay 307, to ground on the sleeve of selector 301. The operation of relay 305 opens at the second lower armaiture and back contact the connection to ground for the control lead causing functions to take place at the toll board to disconnect the trunk from the dial circuit and extend it to a cord circuit. The toll board circuits form no part of this invention and have therefore not been shown. Relay305 in operating its upper armatures opens the circuits for the pulsing relay 305 and the operation of relays 305, 307 and 306 apply a busy tone fr'om the alarm cirevitindicated at 315 and 316 over the second upper armature and frontcontact of relay 307, upper inner armature and front contact of relay 306, upper inner armature and front contact of relay 305 to the tip conductor of the selector 301 to cause the usual supervisory .relay of the cord circuit at the toll board to function to operate alamp to indicate that the called line is busy. This lamp will be alternately lighted and extinguished due to the interrupter shown at 316 for the alternate opening and closing of the busy signal circuit.

If the desired line is idle, there will be no ground connection on the sleeve thereof and relay 307 will therefore not be operated. A circuit will instead be established when relay 314 isreleased for the operation of relay 305 from battery through the winding of the usual cut-0d relay of the desired line (not shown) over the sleeve conductor, and back contact of relay 314, upper inner armature and back contact of relay 307, left-hand armature andfront contact of relay 304, upper windingof'relay 305 to ground on the sleeve conductor. This causes relay 305 to be partially operated and-be completely operated through the circuit hereinbefore traced to the lower inner-armature and front contact to the sleeve conductor. Relay 305 in operating opens the connection to ground for the control lead to transfer the trunk to the operators cord circuitas hereinbefore mentioned. Relay 305 opens the circuit for relay 304 and transfers the trunk from the relay 304 to the transmission circuit of the connector and prepares the circuits for ringing. Relay 305 provides a locking circuit as hereinbefore mentioned through its secondary winding to the ground sleeve to cause the release of relay When the trunk circuit is transferred to the cord at the operators toll board it also replaces a ground on the control lead through the fourth conductor before relay 306 has time to release. Hence relay 306 is held operated from this ground connected through the lower armature and back contact'of relay 307, lower armature and front contact of rel'ay 306 and its lower winding to battery. l Vhen now the operator desires to ring the subscriber this'ground on the control lead is removed permitting relay 306 to release. Relay 306 in releasing closes a circuit for the operation of relay 318 from battery windin rectly t0 the ground on the sleeve. Relay 318 closes a connection to ground for the start lead 322 which corresponds to the start lea-fl relay 32 lalone will be operated to transmit the desired signal in the same manner as relays 40 and L1 were operated in Fig; The signals in this case will be received over lead 326 or 327, which may be connected through the front contacts and armatures of relay 213 to sources 220 and 215 respectively. :It should be noted in this casethat' the circuits from the sources QQO-and 215 will pass through the upper winding of relay 306 so that this relay will serve as the trip relay. l/Vhen now the called subscriber answers a call by removing the receiver from the hook, relay 306 will be operated to open the signaling circuit and cause the release of relays 32!", 324: and 313. The release of relay 313 stops the control equipment from transinitting signals and the 7 release of relay QOO-retrirns the equipment to v the next normal position ElSyll'GlQlIlbGi'OlE described. When relay 306 operates the tall-ring circuit is completed'ircm tl e toll board to the desired subscribers lineover the upper armatures and front contacts or" this relay. After the conversation is completed and the called subscriber hangs up his receiver and the toll v operator abandons the call, the selector 30l releases causing relays 305 and 306 to release which in turn prepare the circuit for energizing the release magnet 308 from battery winding of this magnet, made contacts of the vert1cal off-normal contacts 311, second lower armature and back contact of relay 306, righthand armature and back contact of relay 304 to ground to the second lower armature and back contact of relay 305. i I

It should be understood that while the invention has only been disclosed in connection 'ith two connector circuits and a control circuit it could readily be applied to a plurality of other systems without departing from the i p V tions of one or more impulses oi current from spirit thereof. v

What is claimed is: 1. In a telephone system, a line, a switch,

sources of signaling current, current interrupting devices associated with said switch,

sourcesof signaling current, two relays associated with each switch, a plurality of fer-- a plurality of terminal points'through which said switch has access to said line, and control means responsive to the establishing of a connection from the switch to the line for actuating said devices to apply signaling current to saidline in a particular code of a particular kind and to one side or the other of theline dependingon the terminal point employed tion. s i

2. In a telephone system, a line, a plurality of switches, means for establishing connecin the establishing ofthe connec-- trolling said relays, and means for selectively determining the type of code signals to. be

applied. 2 V

" 3'. Inatelephone system, a line, aplurality of switches, means for estabilshing connections from anyone offsaid switches to said line, means-includingtwo relays associated with each switch for'applying code signals to said line, a common control device for con trolling said relays, means for selectivelyde-' terminingthe type of code signals to be .ap=

beginning of the code. I

4;. In a'telephone system, a lme, a sw1tch, means for establishingconnections between said switch and linewover diflerentlvp'aths,

sources of signaling current, a current interrupter associated with said 'switch',-another current interrupter inthe form of a marginal relay associated with said switch, andmeans responsive to the establishing of acon'nection plied, and means for preventing the application of a selected code signal except at the to said line for controlling said interrupters to transmit different code signals from said sources of said'line depending on the'path over which the connection is 'established.

5. In a telephone system, .a line',la' switch, sources of signaling current, two relays associated with said switch, a plurality of terminal points through which connections may be established to said line, and -means responsive to the establishing of said connec tionsfor controlling said relays to transmit different current code signals over said line depending on the terminal point through which the connections are made.

6. In 'a telephone system, a switch, a line, two sources of signaling current, two relays associated with said switch, a plurality of terminal points in said switch through which connections may be made to said line, and

means responsive to the establishing of such connectlons for controlling said relays to transmit code signals comprlsing combinaeither sourcev depending on the terminal point 'thro'u'ghwhichfsaid connections are .estab lishedfi I 7. In a telephone system, switches, lines,

minalpoints for each line in each switch, a

ing said common switching device to-controlthe control circuit to actuate said relays to transmit code impluses to said line, said sig n'als comprising one or more impulsesfrom control circuit for each set of relays, a switch- 7 either of said sources of current transmitted ove either of the talking conductors in said line with the character of the code signals determined by the terminal point through which the connection is established.

8. In a telephone system, switches, lines, sources of signaling current, two relays associated with each switch, a plurality of terminal points for each line in each switch, a control circuit for each set of relays, a switching device common to said switches for 0011- trolling the control circuit for said relays, means responsive to the establishing of a connection from a switch to a line for actuating said switching device to control the control circuit to actuate said relays to transmit code impulses to said line, said signals comprising one or more impulses from either of said sources of current transmitted over either of the talking conductors in said line with the character of the code signals determined by the terminal point through which the connection is established, and means for preventing said switching device from controlling said control circuit when engaged until said device is in condition to permit said relays to transmit a complete code signal in case said device is employed for control over another connection. V

In witness whereof, I hereunto subscribe my name this 8th day of May, 1930.

HENRY 'HOVLAND. 

